in doing everything i could to make the city a better city. >> reporter: as mayor, she was always in control. her gambling was out of control. >> i thought i could beat that machine, and when it got worse i didn't know i had the silent grenade in my head that could go off at any time. >> reporter: the silent grenade was a golf ball sized tumor doctors removed from her brain. they discovered it two years ago when she started hallucinating. she says she believes the slow growing tumor contributed to her gambling addiction. >> it's not an excuse for my gambling but i think that was, yes, part of it. you lose your sense of control. >> reporter: the tumor could have affected her behavior says her neuropsychologist. >> in about 20% of cases in tumors psychiatric personality or behavioral changes oftentimes are of the first symptom of a tumor. >> she began her gambling run in 2001 a decade earlier. it would have to be a pretty slow growing tumor. >> reporter: halperin says the justice department will drop the charges if she repays the charity and gets help for her addiction. >> after the tu